A typical thermal printhead uses a temperature sensor (e.g., thermistor) integrated with the thermal printhead to measure a printhead temperature. The printhead temperature is used to control the energy applied to the thermal printhead for heating during printing. For example, as the thermal printhead becomes hot during printing, the energy applied to the thermal printhead may be reduced. Reducing the heating, however, may affect print quality, especially if the print medium (e.g., thermal paper) is cold (e.g., in a cold environment).
To insure high-quality thermal printing, both the temperature of the printhead and the temperature of the environment should be used for print-temperature control. In this way, when the printhead temperature and the environment temperature diverge, the heating of the thermal printhead may be compensated so that the print quality does not suffer.
Therefore, a need exists for a thermal printer that monitors both a printhead temperature and an environment temperature and that can adapt its heating to maintain print quality when the printhead temperature and the environment temperature differ.